PR c/17807

	* c-decl.c (undef_nested_function): New variable.
	(pop_scope): Diagnose undefined nested functions.
	(finish_function): Don't attempt cgraph processing or genericizing
	if current top-level function contained an undefined nested
	function.  Reset undef_nested_function at the end of a top-level
	function.

testsuite:
	* gcc.dg/nested-func-3.c: New test.
	* gcc.dg/pr18596-3.c: Expect error for undefined nested function.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@94645 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 16 insertions, 1 deletions

diff --git a/gcc/c-decl.c b/gcc/c-decl.c
index ad76f235de9..0b7b97ede23 100644
--- a/gcc/c-decl.c
+++ b/gcc/c-decl.c
@@ -149,6 +149,11 @@ static int warn_about_return_type;
 
 static int current_extern_inline;
 
+/* Nonzero when the current toplevel function contains a declaration
+   of a nested function which is never defined.  */
+
+static bool undef_nested_function;
+
 /* True means global_bindings_p should return false even if the scope stack
    says we are in file scope.  */
 bool c_override_global_bindings_to_false;
@@ -759,6 +764,12 @@ pop_scope (void)
 	      && DECL_ABSTRACT_ORIGIN (p) != 0
 	      && DECL_ABSTRACT_ORIGIN (p) != p)
 	    TREE_ADDRESSABLE (DECL_ABSTRACT_ORIGIN (p)) = 1;
+	  if (!DECL_EXTERNAL (p)
+	      && DECL_INITIAL (p) == 0)
+	    {
+	      error ("%Jnested function %qD declared but never defined", p, p);
+	      undef_nested_function = true;
+	    }
 	  goto common_symbol;
 
 	case VAR_DECL:
@@ -6376,7 +6387,8 @@ finish_function (void)
      until their parent function is genericized.  Since finalizing
      requires GENERIC, delay that as well.  */
 
-  if (DECL_INITIAL (fndecl) && DECL_INITIAL (fndecl) != error_mark_node)
+  if (DECL_INITIAL (fndecl) && DECL_INITIAL (fndecl) != error_mark_node
+      && !undef_nested_function)
     {
       if (!decl_function_context (fndecl))
         {
@@ -6402,6 +6414,9 @@ finish_function (void)
         }
     }
 
+  if (!decl_function_context (fndecl))
+    undef_nested_function = false;
+
   /* We're leaving the context of this function, so zap cfun.
      It's still in DECL_STRUCT_FUNCTION, and we'll restore it in
      tree_rest_of_compilation.  */